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Abstract

Precise control of the shape and position of double-null divertor configurations in the TCV tokamak has been used to trigger the transition from ELM-free to ELMy ohmic H-mode and back. Pre-programmed modulation of the magnetic axis height (+/- 1.25 cm), with fixed shaping field, caused the plasma to evolve, during a single discharge, between double-null-upper, double-null and double-null-lower configurations, with both X-points remaining close to the last closed flux surface. The transition from ELM-free to ELMy and back again was observed to be synchronous with the configuration modifications. Using this method, several ELM-free and ELMy phases enabled reproducible disruption-free H-mode discharges in TCV lasting up to 1.5 seconds. The plasma density during a long-duration H-mode was directly controlled by feeding back onto the vertical height of the magnetic axis.

Additional information

Authors: DUTCH M J ET AL., Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne (CH)
Bibliographic Reference: Report: LRP 501/94 EN (1994) 10 pp.
Availability: Available from Confédération Suisse, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, 21 avenue des Bains, 1007 Lausanne (CH)
Record Number: 199411471 / Last updated on: 1994-12-06
Category: PUBLICATION
Original language: en
Available languages: en